Sediment core reveals Arctic warm spells

The Arctic has gone through intensely warm periods—warmer than scientists thought was possible—in the last 2.8 million years, according to information collected from the longest sediment core ever collected on land in the Arctic.

“These pollen data provide the first records that are definitively from warm periods of about 400,000 and 1.1 million years ago,” says study author Patricia Anderson, professor emeritus at the University of Washington.